The EU on Monday urged all parties to the landmark Iran nuclear accord to stick to their commitments after US President-elect Donald Trump said he might ditch the deal.

European Union foreign ministers meeting in Brussels said the deal signed last year with Iran by the United States, three EU powers as well as Russia and China must be respected as the bloc seeks to expand economic and other ties.

"The upholding of commitments by all sides is a necessary condition to continue rebuilding trust and allow for continued, steady and gradual improvement in relations between the European Union, its member States and Iran," the ministers said in their conclusions.

The EU welcomed the fact that the US government was now issuing licences for the export of commercial passenger aircraft and related parts and services to Iran and said it hoped they would continue.

Such sales "will be an important signal" for the deal's implementation and contribute to a safer commercial aviation environment, the ministers said.

Under the deal, all nuclear-related sanctions against Iran were lifted in return for Tehran accepting curbs on a programme that Western powers feared would pave the way for atomic weapons.

During his presidential campaign, Trump promised to tear up the Iran nuclear deal, the signature diplomatic breakthrough of Barack Obama's second term, but he has been more circumspect since winning last week's election.

The EU said it is committed to lifting nuclear-related economic and financial sanctions against Iran while engaging with banks and other economic operators "to promote growth in trade and investment."

It said it "remains concerned" with the human rights situation, especially over the frequent use of the death penalty, and underlined the need for equal rights for women and minorities.

The EU, voicing concern about Iran's missile programme, urged Tehran to refrain from ballistic missile tests and urged Iran to "to use its influence on the Syrian regime" of President Bashar al-Assad to end attacks on civilians.